The present invention relates to an apparatus for severing and holding a torn web for a web processing machine and more particularly for a web feed rotary printing press, comprising a knife beam having a stationary knife and arranged across the conveying plane of the web, and furthermore a strike beam having a hump adapted to come into functional engagement with the knife and which by means of an associated push-out means is able to be lifted and lowered, said means being adapted to be activated by a web tear detector.
A device of this type is for instance described in the German patent publication 3,822,497 A1. In the case of prior art devices of this type the knife and the hump of the strike beam are so arranged that the knife may move past a flank of the hump. This leads to an asymmetrical structure and the consequence is that in a case in which one of the two ends of the severed paper is held and the other is released, one respective design is necessary for both alternatives. Since in practice both alternatives occur, the equipment has so far been complex. In conjunction with this it is to be assumed that one run of the torn paper web will generally wind itself up on a roll and therefore has to be released at the point of cutting, while the other run, which extends as far as the tear should be held fast. A further disadvantage of the known devices is that the web may not be reliably severed by means of the knife moving past one flank of the hump on the strike beam. The web, which is then practically running slack owing to the tear is able to move out of the way of the knife. For this reason the known equipment is unsuitable, more particularly in the case of working on thick material. A further and more particularly serious disadvantage of the known equipment is that there is a considerable risk of injury. In this connection it is to be assumed that the knife moving past one flank of the hump is readily accessible from the side.